Approximately 20% of the adult population of the developed world consistently snores at night at volumes high enough to disturb sleeping partners. This results in strained relationships and the possible breakdown of the family unit, as well as real physiologic harm to the snorer. Of audible snorers, approximately one in five suffers from obstructive sleep apnea (OSA), a condition in which tissues of the nasopharynx fall into positions that block the airway, restricting breathing during sleep to an extent that causes the patient repeated cycles of breathing cessation (apnea) and subsequent gasping for air without regaining consciousness. The OSA patient is deprived of restful sleep and suffers from poor tissue oxygenation, impaired memory, cognition, and daytime mental functioning, and in extreme cases runs the risk of sudden death from oxygen deprivation (asphyxiation) during sleep.
Remedies for OSA start with prescribed weight loss, as approximately 25% of OSA patients can be cured by losing significant fat around the neck. The majority of OSA patients, however, are not obese. For them, the “gold standard” therapy is continuous positive airway pressure (CPAP) treatment. This non-surgical approach to treating OSA involves requiring the patient to wear a head-mounted electric-powered breathing apparatus every night, which mechanically forces air down the patient's windpipe, blowing open the floppy tissue that would otherwise be obstructing the nasopharynx with each breath cycle. The obvious disadvantage of CPAP therapy is that it is unpleasant at best and psychologically debilitating at worst to a patient's nightlife, not to mention uncomfortable to wear.
Less unpleasant, but similarly requiring patient compliance with nightly rituals, is the use of mandible-displacing dental appliances. These devices are similar to dental “night guards” commonly used to prevent teeth grinding (nocturnal bruxism), such as “Silent Nite” or “Pivot Solution.” They have the added feature of a configuration that pushes the mandible forward (in the ventral direction in the sagittal plane) to cause the base of the tongue to move away from the back of the throat, thereby opening the airway. An implantable electronic Tongue Nerve Stimulator (the Inspire II Upper Airway Stimulation System) has also been FDA cleared and is being used in severe OSA cases in which the treating physician is confident that the patient's obstruction is specifically due to the tongue and not the palate tissues. These devices suffer from a significant limitation, however, because only approximately 10% of non-obese snorers owe their condition to tongue-base airway obstruction. In the vast majority of snoring and mild OSA cases, the soft palate and uvula are the cause of the obstruction. These tissues become longer and floppier with age, making OSA increasingly common in advancing decades.
Two approaches have been commercialized to directly intervene and correct the soft palate's tendency to fall back and block the airway. In 1990, Dr. Yves-Victor Kamami, a surgeon of the Marie-Louise Clinic in France published reports of his short-term success treating OSA with a surgical procedure he called Laser-assisted Uvulopalatoplasty (LAUP). This procedure enjoyed popularity in over the next ten years, until the late 1990s when additional publications (Finkelstein, Schmidt and others) showed that in many cases, laser-assisted uvulopalatoplasty for moderate snorers without OSA (“nonapneic snorers”) could cause OSA to begin, or worsen existing mild OSA, attributable to thermal damage inflicted by the laser. The laser appeared to cause scar tissue that crowded and thereby reduced the airspace in the pharynx (it induced progressive palatal fibrosis, accompanied by medial traction of the posterior tonsillar pillars leading to velopharyngeal insufficiency). Scar tissue also tends to make the airway more likely to collapse during sleep, since it lacks the resiliency of healthy tissue. Hence, LAUP could be a medically-induced (“iatrogenic”) cause of sleep apnea.
In 2003, Restore Medical launched the Pillar Palatal Implant System, consisting of a hollow-bore needle hand-held applicator that deployed a stiff rod-shaped implant into a patient's soft palate. A physician would deploy an average of 2-3 Pillar rods as permanent implants to stiffen the palate and thereby make it less likely to obstruct the airway. The main challenges were that (1) the Pillar implants, no matter how many are used, do not shorten the soft palate, and therefore cannot pull it away from the sit of obstruction, and (2) the implants had a persistent rate of partial extrusion in the post-procedure period.